Seagorath appeared in the 1971 TV series called Return of Ultraman. Appearing late one night with his mate, the two monsters Seagorath and Seamons attacked a ship full of diamonds and gems by using their weather-controlling powers. After attacking, they disappeared beneath the waves.
Later on Seamons was having some trouble on land as she was confronted by MAT, and so she called out to her mate. Seagorath heard the call and emerged from the bottom of the ocean to aid her. Using his own weather control powers, Seagorath created a Tsunami hundreds of feet tall and directed it towards Japan. Hideki Go transformed into Ultraman Jack then created an Ultra Barrier and successfully repelled the tsunami back at Seagorath subduing the monster, but lost most of his energy in the process. Seamons easily knocked around Jack, forcing him to leave. MAT then realized that Seamons and Seagorath are trying to mate and use the diamonds for preparation.
Later that day, Seamons was attacked again, this time by Japan's SDF. Seagorath soon appeared himself hearing Seamons call again and both mates used their powers to create a tornado to eliminate the SDF. To ensure they wouldn't attack his mate again, Seagorath stayed with his mate on dry land and the two began their mating process. The next day, Ultraman Jack returned to battle once again but he had a very difficult time dealing with both Seamons and Seagorath and their combined weather controlling powers. Luckily, a newly-tested Laser Gun SP-70 was created by MAT and fired at Seagorath's massive horn, successfully destroying it. Without their advantage of Seagorath's weather control, both mates retreated back into the ocean.